Stub drivers



May 8, 1962 T. R. HALL 3,033,297

STUB DRIVERS vllrrlllfllllllfqlalap;

46 THOMAS R, HALL T. R` HALL STUB DRIVERS May 8, 1962 2 Sheets-Sheet 2 Filed Feb. 26, 1960 INVENTOR.

THOMAS R. HALL ATTORNEY arent Odce 3,033,297 Patented May 8, 1962 3,033,297 STUB DRIVERS Thomas R. Hall, Portland, Greg., assignor to McCabe- Powers Body Company, Berkeley, Calif., a corporation of California Filed Feb. 26, 1963, Ser. No. 11,360 15 Claims. (Cl. 175-144) This invention relates in general to new and useful improvements in stub drivers and, more particularly, to portable stub drivers for use in utility service operations and the like.

It has been found that the ground-imbedded portion of a conventional wooden pole, such as `a telephone or telegraph pole, will become eroded in the course of time, and the pole fill either break oif or become so weak as to be `in danger of doing so. Under such circumstances a socalled shoring stub is placed vertically in the ground alongside the telephone pole with a portion extending several feet above the ground in `axial abutment with the pole. The pole and the stub are then -rigidly connected by steel bands, long bolts, or other suitable means, thereby reinforcing the pole installation. One of the major problerns, however, in this type of pole repair is the placement of the stub into the ground against the pole in vertical alignment `and in axially abutting relationship. The most common practice, at present, is to employ manual labor and dig a hole several feet deep along one side of the damagedor eroded pole, place the stub in position, connect it to the pole, and then back-fill. Obviously, this is' a time-consuming, expensive, `and laborious procedure.

' lt is, therefore, the primary object of the present invention to provide a power-actuated mechanical device capable of driving a stub into the ground in snug axial abutment against a telephone pole or the like.

lt is also an object of the present invention to provide a device of the type stated which can be easily and conveniently transported from place to place.

It is a further object of the present invention to provide an improved stub driver with positive downward hammer stroke.

It is an additional object of the present invention to provide a hydraulically driven stub driver wherein positive-driving force is applied to the hammer thereof during both the upward and downward stroke.

With the above and other objects in view, my invention resides in the novel feature-s of form, construction, arf rangement, and ycombination of parts presently described and pointed out in the claims.

In the Kaccompanying drawings (two sheets) FIG. 1 is a fragmentary side elevational View of a truck equipped with a stub driver constructed in accordance with and embodying the present invention;

FIG. 2 is a fragmentary sectional View taken along line 2 2 of FIG. l;

FiG. 3 is `a front elevational view of the stub driver constructed in accordance with 'and embodying the present invention;

FIGS. 4 and 5 are transverse sectional views taken along lines 4 4 and 5 5, respectively, of FIG. 3;

FIG. 6 is a perspective view of the hammer forming a part of the present invention;

FlGS. 7, 8, 9, l0, and l1, are fragmentary sectional views taken along lines 7 7, 8 8, 9 9, 10 10, and 11 11, respectively, of FIG. 3; and

FIG. 12 is a schematic diagram of the hydraulic system forming a part of the present invention.

Referring now in more detail and by reference characters to the drawings which illustrate a preferred embodiment of the present invention, A designates a vehicle having a chassis 1 carrying a conventional derrick 2 including a boom 3 and a conventional hydraulic cylinder 4 2 by which the position of the boom may be varied. Th boom 3 is provided with a conventional sheave-block 5 in which a pulley-wheel 6 is rotatably mounted. Preferably, though not necessarily, the truck A may be also provided with ground-engaging jacks 7 for stabilizing the chassis against movement on its springs or other suspension means when the vehicle A'is in work position.

B designates ia stub driver including a swivel-fitting 8 adapted for engagement with the sheave-block 5 or any other suitable element adjacent to the upper end of the boom whereby the stub driver B may be suspended therefrom. At its lower end the swivel fitting 8 is provided with a clevis 9, which, in turn, is removably fastened to the upper end of a slide frame 10 comprising an elongated vertical U-shaped channel 11 having a web 12 and a pair of parallel flanges 13, 14. A top plate 15 is welded across the upper end 16 of the channel 11. Similarly welded to the lower end 17 of the channel 11 is a base plate 18 provided with a clearance slot 19 of such size and proportions as to extend around and accommodate the stub S. Mounted above the base plate 18 rearwardly of the web 12, by means of motor support bracket plates 20, is -a reversible hydraulic motor 21 provided with a drive shaft 22 which extends through a bearing 23 mount-V ed in the web 12 and is providedon the forward end with a sprocket 24. The hydraulic motor 21 is operatively connected to `a, source of hydraulic duid under pressure, as shown in FIG. l2. This hydraulic circuit includes a switching valve V whereby the hydraulic motorV 21 can be driven in either direction. Preferably, though Anot necessarily, a conventional slip clutch c is interposed in the drive shaft 23 for purposes presently more fully .ap-

pearing.

Attached to the upper end16 of the channel 11, and extending inwardly therefrom is la shaft 25 on which a second sprocket`26 is suitably journaled, the sprocket 26 being' above and in alignment with the sprocket 24. The flanges 13, 14, are provided with matching transversely aligned trackways 27, 28, which extend longitudinally throughout the length of the channel 11 and are sized for sliclably receiving the sides 29, 30, of a slideplate 31 forming the principal part of a hammer 32. Welded or otherwise rigidly mounted on the slide-plate 31 is a heavy impact-block 33 which is reinforcedtby a pair of gussets 34, 35, which are also welded to the slideplate 31. Extending rearwardly from the slide-plate 31 is a rectangular bracket 36 provided with a pair of spaced aligned apertures 37, 38, and in spaced relationship from the bracket 36 and Ialso extending rearwardly from the base-plate 31 is a bumper 39 which is preferably, though not necessarily, fabricated from a short piece of I-beam, `as best seen in FIG. 6. The bumper 39 is adapted to coact with a hammer decelerator 40 which consists of a hollow cylindrical shell 41 mounted on the base-plate 18 and containing a plurality of rubber disks 42 stacked within the shell 41, and a cylindrical impact bar 43 slidably seated in the shell 41 atop the disks 42. When the hammer 32 reaches the lower limit of its downward stroke, the bumper 39 engages the impact bar 43 whereupon the impact is somewhat cushioned by the compression of the rubber disks 42 in the shell 41. A second hammer decelerator 40', including a shell 41', fa plurality of rubber disks 42', and an impact bar 43', is mounted at the top 15 of the slide-frame 10 in such position that the upper end of the lbumper 39 will strike the impact bar 43 as the hammer 32 reaches its uppermost position. It should be noted that the shells 41, 41', are respectively provided with collars 44, 44', having apertures 45, 45', for retentive engagement with annular shoulders 46, 46' formed by diametrally enlarged head-portions 47, 47' of the impact bars 43, 43', whereby to retain the impact bars 43, 43', Within the shells 41, 41'.

`adjusting crank 69 is threadedly inserted thereon. adjustment of the adjusting crank 69, the chain 61 is A conventional sprocket chain 48 is trained around the sprockets 24, 26, and is attached at each of its ends to link fasteners 49, 50, which, in turn, are attached to bolts 51, S2, the bolts 51, 52, respectively, extending in opposite directions through the apertures 37, 38, in the bracket 36. A plurality of rubber washers 53, and metal washers 54 are placed over each of the bolts 51, 52, in alternating order, in each case a rubber washer 53 abutting the bracket 36 and a metal washer 54 terminating the combination of washers 53, 54. A pair of conventional nuts 55, 56, are threaded upon the ends of the bolts 51, 52, whereby to operatively secure the bolts 51, 52, the rubber washers 53, and the metal washers 54 to the bracket 36. As the bolt 51 is attached to one end of the chain 48 and the bolt 52 is attached to the other end of the chain 48, a continuous loop is provided having its ends connected to the bracket 36 through the shock mounting provided by the combination of washers 53, 54, about the bolts 51, 52.

Outwardly extending from the lateral ange 14 of the channel 11 and rigidly secured thereto is a bracket 57 provided with an aperture 58 adapted for receiving a pin S9 having an eyelet 60 in which a length of chain 61 is inserted. The pin 59 is provided lat its rearward end with a flattened head 62 and a conventional spring 63 is interposed between the bracket 57 and the head 62 of the pin 59 whereby to bias the pin rearwardly with respect to the channel 11. Similarly, the lateral ange 13 is also provided with an outwardly extending bracket 64 provided with an aperture 65 adapted for receiving a pin 66 having an eyelet 67 and a threaded end 68. The .chain 61 is attached at its other end to the eyelet 67 of the pin 66. An adjusting crank 69 having a handle 70 .is threadedly mounted over the threaded end 68 of the pin 66. Thus, when the chain 61 is placed around a pole P the adjusting crank 69 may be rotated, and the chain 61 drawn tightly against the pole P so that the forwardly presented margins 71, 72, of the channel 11 will be drawn toward and securely held lengthwise against the pole P. It should be noted that when the stub driver `B is drawn tightly against the pole P, the forwardly pre- -sented margins 71, 72, of the anges 13, 14, are in ushwise contact with the pole P providing the proper vertical alignment between the pole P and the stub driver B.

In use, the stub S, which is preferably a length of I-beam, is placed vertically against the pole P with the longitudinal margins of its flanges abutting axial portions of the pole P, as shown in FG. 2. The stub driver B is then brought into abutment with the pole P so that the lower end thereof embraces the stub S and the upper portion, above the stub S, embraces a side of the pole P. The clearance slot 19 in the base plate 18 permits the stub S to be sufticiently free for downward driven movement. Thereupon, the chain 61, which is securely attached to the pin 59 in the bracket 57, is cinched around the pole P and the threaded end 68 of the pin 66, which is secured to the other end of the chain 61, is placed 4through the aperture 65 in the bracket 64 whereupon the By drawn tightly about the pole P and the lateral margins `7l, 72, of the flanges 13, 14, are held in ushwise axial abutment along the curved surface of the pole P. The

`hydraulic motor 21 is then conventionally connected to `the source of hydraulic fluid on the vehicle A, and the switching valve V suitably manipulated so that the hammer 32 is alternately raised and lowered by means of the loop of chain 48 which is trained about the sprockets 24, 26, and connected to the hammer 32. As the hammer 32 is elevated to its upper limit, the bumper 39 'will strike the upper hammer decelerator 40' and the upwardly moving hammer 32 will be cushioned by the rubber disks 42. In the event that the operator fails to stop` the ascent of the hammer 32 at the proper time, the slip-clutch c will prevent chain rupture. The operator then reverses the switching valve V, whereupon the hammer 32 will be positively driven downwardly by a combination of the forces of gravity and the hydraulic force supplied by the hydraulic motor 21 through the cable chain 48 until the hammer 32 either strikes the stub S or the lower hammer decelerator 40, the latter serving as a limit-determining, as well as safety, device. The slip-clutch c also prevents breakage of the chain 48 on the downward stroke. After a series of successive strokes, when the hammer 32 begins to strike in the hammer decclerator 40, the stub S will have been driven as far as possible for this particular setting of the stub driver B. If the stub S is a long one, or if for some other reason it must be driven down further into the ground, the chain 61 may be loosened and the stub driver B dropped to a new lower position in reference to the stub S. When the stub S has been driven to the desired depth in the ground, the stub driver B can be disconnected from the pole P and stowed away on the vehicle A by conventional manipulation of the boom 3.

It should be understood that changes and modications in the form, construction, arrangement, and combination of the several parts of the stub drivers may be made and substituted for those herein shown and described without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. A stub driver comprising a base, guide means operatively mounted on said base, impact means slidably mounted in said guide means, driving means consisting of a reversible hydraulic motor, two vertically spaced pulleys located in said guide means, one of said pulleys being mounted on and driven by said motor, a continuous element trained around said vertically spaced pulleys. said continuous element also being operatively connected -to said impact means, means for reversing the direction of said motor and said continuous driving element for driving said impact means in alternate directions in said guide means, and means for securing said driver in a substantially vertical position.

2. A stub driver comprising an elongated channel adapted to be disposed in a substantially vertical position provided with spaced parallel ways located for vcrtical disposition when the channel is vertical, impact means slidably mounted in said ways for reciprocative movement upwardly and downwardly, and driving means consisting of a reversible hydraulic motor, two vertically spaced pulleys located in said guide means, one of said pulleys being mounted on and driven by said motor, a continuous element trained around said vertically spaced pulleys, said continuous element also being operatively connected to said impact means, means for reversing the direction of said motor and said continuous driving element for alternately lifting said impact means and driving it positively downward so that the downward striking force of the impact means is a combination of its weight and the driving force of said driving means.

3. A stub driver comprising a base, a channel rigidly secured to and upwardly extending from said base, a trackway operatively mounted in said channel, hammer means slidably mounted in said guide means, driving means consisting of a reversible hydraulic motor, two vertically spaced pulleys located in said guide means, one of said pulleys being mounted on and driven by said motor, a continuous element trained around said vertically spaced pulleys, said continuous element also being operatively connected to said hammer means, means for reversing the direction of said motor and said continuous driving element for driving said hammer means in alternate directions to said trackway, and means for securing said driver to a pole-like object which is secured to the ground.

4. A stub driver comprising a base, a channel rigidly secured to said'base and having a pair of spaced parallel wallsextending upwardly therefrom, each of said walls being provided with :a complementary aligned trackway, a hammer slidably mounted in said trackways, a bumper mounted on and extending rearwardly from said hammer, means operatively mounted at each end of said aligned trackways for decelerating said hammer, said decelerating means being aligned and located for cooperation with said bumper on said hammer to cause said hammer to decelerate rapidly at the end of the upward and ldownward strokes, driving means consisting of a reversible hydraulic motor, two vertically spaced pulleys located in said guide means, one of said pulleys being mounted on and driven by said motor, a continuous element trained around said vertically spaced pulleys, said continuous element also being operatively connected to said hammer, means for reversing the direction of said motor and said continuous driving element for driving said hammer in alternate directions in said trackways, and means for securing said driver to a pole-like object which is secured to the ground.

5. A stub driver comprising a base, a channel rigidly secured to said base and having a pair of spaced parallel walls extending upwardly therefrom, each of said walls being provided with a complementary aligned trackway, upper and lower deceleration housings rigidly mounted at opposite ends of said channel in aligned relationship, each of said housings being provided with a retention collar having an aperture, a plurality of resilient disks loosely disposed in each of Saiduhousings, each of said housings also being provided with an impact bar having an enlarged head disposed within said housing in substantial abutment with one of said resilient disks therein, each of said impact bars also including a diametrally reduced end projecting through the aperture in said housing, a hammer slidably mounted in said trackways, a bumper mounted on and extending rearwardly from said hammer, said bumper being provided with an upwardly presented surface for cooperating with said impact bar and resilient disks in said rst housing to decelerate said hammer at the top of said trackway and a downwardly presented surface for cooperating with said impact bar and resilient disks in said lower housing to decelerate said hammer at the lower end of said trackway, driving means consisting of a reversible hydraulic motor, two vertically spaced pulleys located in said guide means, one of said pulleys being mounted on and driven by said motor, a continuous element trained around said vertically spaced pulleys, said continuous element also being operatively connected to said hammer means, and means for reversing the direction of said motor and said continuous driving element whereby to drive said hammer means in alternate directions in said trackway.

6. A stub driver comprising a base, a channel rigidly secured to said base and having ay pair of spaced parallel walls extending upwardly therefrom7 each of said walls being provided with a complementary aligned trackway, upper and lower sprockets journaled on the channel adjacent o-pposite ends thereof, =a hammer slidably mounted in said trackways for reciprocative movement between the sprockets, a bumper mounted on and extending rearwardly from said hammer, means for decelerating said hammer operatively mounted at each end of said aligned trackw-ay, said decelerating means being aligned and located for cooperation with said bumper on said hammer to cause said hammer to decelerate rapidly at the end of the upward and downward strokes, a chain operatively connected to said hammer and trained around the sprockets, reversible hydraulic motor driven means, and a switching valve operatively connected to said motor driven means, said lower sprocket being operatively connected to and driven by said motor driven means for driving said chain and hammer in alternate directions in said trackways, and means for securing said driver to a pole-like object which is secured to the ground.

7. A stub driver comprising a base, a channel rigidly securedD to said base and having a pair of spaced parallel walls extending upwardly therefrom, each of saidwalls being provided with a complementary aligned trackway, a hammer slidably mounted in said trackways, ya bumper mounted on and extending rearwardly from said hammer, ymeans mounted at each end of said aligned trackways for decelerating said hammer operatively, said decelerating means being aligned and located for cooperation with said bumper on said hammer to cause said hammer to decelerate rapidly at the end of the upward and downward strokes, a lirst driving member operatively mounted on said channel at oneV end of said trackways, a reversible hydraulic motor operatively mounted at the other end of said trackways and being provided with a rotatable shaft which projects into said trackways, said motor being provided with means for operatively connecting said motor to a power source for reversible operation whereby to apply power to both the upward and downward strokes, a second driving member rigidly mounted on said shaft, a flexible drive means secured at both ends to said hammer and being routed Iabout said driving members in la continuous loop, and means for securing said driver to a pole-like object which is secured to the ground.

8. A stub driver comprising a base, a channel rigidly secured to said base and having a pair of spaced parallel walls extending upwardly therefrom, each of said walls being provided with `a complementary aligned trackway, a hammer slidably mounted on said trackways, a bumper mounted on and extending rearwardly from said hammer, means for decelerating said hammer operatively mounted at each end of said aligned trackways, said decelerating means being aligned and located for cooperation with said bumper on said hammer to cause said hammer to decelerate rapidly at the end of the upward and downward strokes, a lirst sprocket operatively mounted on said channel at one end of said trackways, `a reversible hydraulic motor operatively mounted at the other end of said trackways and being provided with a rotatable shaft which projects into said trackways, said motor being provided with means for operatively connecting said motor to a power source for reversible operation whereby to applyfpower to the upward and downward strokes, a second sprocket rigidly mounted on said shaft, a chain routed :about both 'of said sprockets, Iand means for resiliently connecting both ends of said chain to said hammer whereby to form a continuous loop and to absorb shock as said bumper strokes said decelerating means.

9. A stub driver comprising a base, a channel rigidly secured to said base and having a pair of spaced parallel walls extending upwardly therefrom, each of said walls being provided with a complementary aligned trackway, a hammer slidably mounted on said trackways, a bumper mounted on and extending rearwardly from said hammer,

u means for decelerating said hammer operatively at each end of said'aligned trackways, said decelerating means being aligned and located for cooperation with said bumper on said hammer to cause said hammer to decelerate rapidly at the end of the upward and downward strokes, a first sprocket operatively lmounted on said channel at one end of said trackways, a reversible hydraulic motor operatively mounted at the other end of said trackways and being provided with a rotatable shaft which projects into said trackways, said motor being provided with means Ifor operatively connecting said motor to a power source for reversible operation whereby to apply power to the upward and downward strokes, a second sprocket rigidly -mounted on said shaft, a plate rigidly connected to and extending rearwardly from said hammer, said plate being spaced from said bumper and being provided with a pair of spaced apertures, a pair of bolts projecting through each of said apertures in opposite directions, a plurality of resilient washers, a plurality of rigid washers, said resilient and rigid washers being alternately disposed about each of said bolts, eachof said' bolts being secured to said plate and said washers by a nut, a chain trained around said sprockets, and means for connecting the ends of said chain to said bolts whereby to form a continuous loop of chain connected at its ends to said plate on said hammer.

l0. A stub driver comprising a base, a channel rigidly secured to said base and having a pair of spaced parallel walls extending upwardly therefrom, each of said walls being provided with a complementary aligned trackway, a hammer slidabiy mounted on said trackways, a bumper mounted on and extending rearwardly from said hammer, means for decelerating said hammer operatively at each end of said aligned trackways, said decelerating means being aligned and located for cooperation with said bumper on said hammer to cause said hammer to decelerate rapidly at the end of the upward and downward strokes, a rst sprocket operatively mounted on said chaunel at one end of said trackways, a reversible hydraulic motor operatively mounted at the other end of said trackways and being provided with a rotatable shaft which projects into said trackways, said motor being provided with valve means for reversibly connecting said motor to a source of hydraulic fluid under pressure whereby to apply power to the upward and downward strokes, a secohnd sprocket operatively mounted on said shaft, a plate rigidly connected to and extending rearwardly from said hammer, said plate being spaced from said bumper and being provided with a pair of spaced apertures, a pair of bolts projecting through each of said apertures in opposite directions, a plurality of resilient washers, a plurality of rigid washers, said resilient and rigid washers being alternately disposed about each of said bolts, each of said bolts being secured to said plates and said washers by a nut, a chain operatively trained around the sprockets, and means for connecting the ends of said chain to said bolts whereby to form a continuous loop of cable connected at its ends to said plate on said hammer, said resilient and rigid washers being arranged in such manner that a resilient washer abuts said plate and a rigid washer abuts said nut.

1l. A stub driver comprising a base, a channel rigidly secured to said base and having a pair of spaced parallel walls extending upwardly therefrom, each of said walls being provided with a complementary aligned trackway, a hammer slidably mounted on said trackway, bumper means consisting of an I-beam mounted on and extending rearwardly from said hammer, means for decelerating said hammer operatively at each end of said aligned trackways, said decelerating means being aligned and located for cooperation with said bumper means on said hammer to decelerate rapidly at the end of the upward and downward strokes, a first sprocket operatively mounted on said channel at one end of said trackways, a reversible hydraulic motor operatively mounted at the other end of said trackways and being provided with a rotatable shaft which projects into said trackways, said motor being provided with means for operatively connecting said motor to a power source for reversible operation whereby to apply power to the upward and downward strokes of said hammer, a second sprocket rigidly mounted on said shaft, a plate rigidly connected to and extending rearwardly from said hammer, said plate being spaced from said bumper means and being provided with a pair of spaced apertures, a pair of bolts projecting through each of said apertures in opposite directions, a plurality of resilient washers, a plurality of rigid washers, said resilient and rigid Washers being alternately disposed about each of said bolts, each of said bolts being secured to said plate and said washers by a nut, a chain trained around said sprockets, and means for connecting the ends of said chain to said bolts whereby to form a continuous loop of chain connected at its ends to said plate on said hammer.

12. A stub driver comprising a base, a channel rigidly secured to said base and having a pair of spaced parallel walls extending upwardly therefrom, each of said walls being provided with a complementary aligned trackway, a hammer slidably mounted on said trackway, bumper means consisting of an l-beam bumper mounted on and extending rearwardly from said hammer, hammer decelerating means consisting of a hollow cylindrical wall containing a plurality of rubber disks, an impact bar seated atop said disks and being mounted on said base plate, means for decelerating said lhammer operatively at each end of said aligned trackways, said decelerating means being aligned and located for cooperation with said bumper means on said hammer to cause said harnmer to decelerate rapidly at the end of the upward and downward strokes, a iirst sprocket operatively mounted on said channel at one end of said trackways, a reversible hydraulic motor operatively mounted at the other end of said trackways and being provided with a rotatable shaft which projects into said trackways, said motor being provided with means -for operatively connecting said motor to a power source for reversible operation whereby to apply power to both the upward and downward strokes, a second sprocket rigidly mounted on said shaft, a plate rigidly connected to and extending rearwardly from said hammer, said plate being spaced from said bumper means and being provided with a pair of spaced apertures, a pair of bolts projecting through each of said apertures in opposite directions, a plurality of resilient washers, a plurality of rigid washers, said resilient and rigid washers being alternately disposed about each of said bolts, each of said bolts being secured to said plate and said washers by a nut, a chain trained around said sprockets, and means for connecting the ends of said chain to said bolts whereby to form a continuous loop of chain connected at its ends to said plate on said hammer.

13. A stub driver comprising a base, a channel rigidly secured to said base, and having la pair of spaced parallel walls extending upwardly therefrom, each of said walls being provided with a complementary `aligned trackway, a hammer slidably mounted on said trackway, bumper means consisting of an I-beam bumper mounted 0n and extending rearwardly from said hammer, hammer decelerating means consisting of a hollow cylindrical wall, a plurality of rubber disks, an impact bar seated atop said disks and being mounted on said ybase plate, means for decelerating said hammer operatively at each end of said aligned trackways, said decelerating means being aligned and located for cooperation with said bumper means on said hammer to cause said hammer to decelerate rapidly at the end of the upward and downward strokes, a rst sprocket operatively mounted on said channel at one end of said trackways, a reversible hydraulic motor operatively mounted at the other end of said trackways and being provided with a rotatable shaft which projects into said trackways, said motor being provided with means for operatively connecting said motor to a power source for reversi-ble operation whereby to apply power to the upward and downward strokes, a second sprocket rigidly mounted on said shaft, a plate rigidly connected to and extending rearwardly from said hammer, said plate being spaced from said bumper means and being provided with a pair of spaced apertures, a pair of bolts projecting through each of said apertures in opposite directions, a plurality of resilient washers, a plurality of rigid washers, said resilient and rigid washers being alternately disposed about each of said bolts, each of said bolts being secured to said plate and said washers by a nut, a chain trained around said sprockets, means for connecting the ends of said chain to said bolts whereby to form `a continuous loop of chain connected at its ends to said plate on said hammer, and means for securing said driver to a polelike object which is secured to the ground.

14. A stub driver comprising a base, a channel rigidly secured to said base and having a pair of spaced parallel walls extending upwardly therefrom, each of said walls 'being provided with a complementary aligned trackway, a hammer slidably mounted on said trackway, bumper means consisting of an I-beam bumper mounted on and extending rearwardly from sa-id hammer, hammer decelerating means consisting of a hollow cylindrical wall, a plurality of rubber disks, an impact bar seated atop said disks and being mounted on said base plate, means for decelerating said hammer operatively at each end of said aligned trackways, said decelerating means being aligned and located for cooperation with said bumper means on said hammer to cause said hammer to decelerate rapidly `at the end of the upward and downward strokes, a rst sprocket operatively mounted on said channel at one end of said trackways, a reversible hydraulic motor operatively mounted at the other end of said trackways and being provided with a rotatable shaft which projects into said trackways, said motor being provided with means for operatively connecting said motor to a power source for reversible operation whereby to apply power to the upward and downward strokes, a second sprocket rigidly mounted on said shaft, `a plate rigidly connected to and extending rearwardly from said hammer, said plate being spaced from said bumper means and being provided with a pair of spaced apertures, a pair of bolts projecting through each of said apertures in opposite directions, a plurality of resilient washers, a plurality of rigid washers, said resilient and rigid washers being alternately disposed about each of said bolts, each of said bolts being secured to said plate and said washers by a nut, `a chain trained around said sprockets, means -for connecting the ends of said chain to said bolts whereby to -form a continuous loop of chain connected at its `ends to said plate on said hammer, and chain means for securing said driver to a pole-like object which is secured to `the `ground whereby said chain can be cinched around and tightly drawn against said pole so that said channel will be drawn against and immediately lheld lengthwise against said pole.

15. A stub driver comprising a base, guide means operatively mounted on said base, impact means slidably mounted in said guide means, driving means consisting of a reversible hydraulic motor, two vertically spaced pulleys located in said guide means, one or" said pulleys being mounted on and driven by said motor, a continuous driving element trained around said pulleys and operatively connected to s-aid impact means whereby said driving means will drive said impact means in said guide means alternately in an upward and downward stroke, means for reversing the direction of said motor and said driving element ywhen the impact means reaches the upper limit of the upward stroke and lower limit of the downward stroke, and means for securing said driver in a substantially vertical position.

References Cited in the tile of this patent UNITED STATES PATENTS 1,375,066 Rowe Apr. 19, 1921 1,586,784 Creech lune 1, 1926 2,593,186 Richardson Apr. 15, 1952 2,599,995 Hobson June 10, 1952 2,792,689 Phares May 21, 1957 

